How to change background color of an HTML input field on content change..??

[bucchi]

Hi,

I have an input field and I have to change the background color when the contents change.
The contents are changed by a pop-up. On submit of the pop-up the contents change.How can I change the input background color?

Thanks

[tj111]

document.getElementById('input_id_here').style.backgroundColor = "red";
//dunno why its putting the space in "background"
 

[mrhoo]

input_reference.onchange=function(e){
    e= window.event? event.srcElement: e.target;
    e.style.backgroundColor = "red";
}